Oil oxidation is a undesired process that commonly occurs in oil containing food products. If allowed to progress freely, oil oxidation causes these food products to develop an undesirable, rancid flavour. Unsaturated and especially polyunsaturated fatty acid residues that abundantly present in vegetable oils are the prime source of rancid smelling oxidation products.
Oil oxidations are strongly catalyzed by free metal ions, such as iron and copper ions. Traditionally, ethylenediaminetetraacetic acid (EDTA) has been used in food products to prevent oil oxidation and spoilage due to its capacity to chelate metals. EDTA, however, is a synthetic or artificial ingredient.
Within the food industry an increasing effort is made to remove artificial ingredients from food products and to replace them with natural alternatives. Owing to its effectiveness, reasonable cost, and lack of viable alternatives, however, EDTA has so far been one of the more difficult artificial ingredients to replace. Attempts so far to replace or remove EDTA from foods and beverages have yielded disappointing results.
US 2010/0028518 describes an oxidatively stable comestible, such as a mayonnaise, that is substantially free of EDTA and that comprises an effective amount of nicotianamine.
US 2010/0159089 describes an oxidatively stable comestible, such as an mayonnaise, that is substantially free of EDTA and that comprises a hydrolyzed polysaccharide having a plurality of side chains with carboxylic acid groups in an amount effective to provide oxidative stability therein; the polysaccharide is hydrolyzed such that the average polysaccharide chain length is about 2 to about 4 molecules and has an average molecular weight of about 300 to about 900 Daltons.
The use of balsamic vinegar in edible emulsions is known. WO 2010/124870 A1, WO 2008/118850 A2, and KR 100 792 811 B1 disclose salad dressings containing balsamic vinegar. Also various salad dressings containing balsamic vinegar are commercially available from supermarkets. However, mayonnaise-type emulsions containing balsamic vinegar are not known. Mayonnaises generally distinguish from salad dressings by being more viscous and having a pale, slightly yellow colour, and by containing ingredients originating from eggs, in particular egg yolk.
It is known that traditional balsamic vinegar has strong antioxidant activity. This antioxidant activity is related to the positive effects of the antioxidants in vivo, after consumption of the balsamic vinegar. There is no suggestion to use balsamic vinegar as an ingredient in emulsions to prevent oil oxidation. Tagliazucchi et al. (Journal of Food Biochemistry, 34 (2010), 1061-1078) observe that during aging of traditional balsamic vinegar low molecular weight compounds are progressively incorporated into the melanoidins skeleton and may contribute significantly to the antioxidant activity of high-molecular-weight melanoidins. According to the authors among these compounds, it has been shown that antioxidant phenolic compounds are progressively incorporated into the melanoidins skeleton during the aging. The authors further conclude that apart from their bioavailability traditional balsamic vinegar melanoidins and low-molecular weight antioxidants may exert their effect on the digestive tract where they can play an important role in protecting the gastrointestinal tract itself from oxidative damage.
Tagliazucchi et al. (European Food Research and Technology, 227 (2008), 835-843) describe the extraction of high molecular weight (>10 kDa) melanoidins from traditional balsamic vinegar. Both melanoidins and polyphenols in traditional balsamic vinegar each contribute about 45% to the antioxidant activity of the traditional balsamic vinegar.
Verzelloni et al. (Food Chemistry, 105 (2007), 564-571) disclose that antioxidant activity of the vinegar aqueous fractions that cannot be attributed to phenolic acids is due to the Maillard products or other antioxidant compounds.